using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace Sec_scan漏洞扫描系统.Sec_Config
{
    /// <summary>
    /// DES加解密方法
    /// </summary>
    public class Sec_DesThreDes
    {
        /// <summary>
        /// 3DES 加密(基于DES，对一块数据用三个不同的密钥进行三次加密，强度更高)
        /// </summary>
        /// <param name="encryptText">待加密密文</param>
        /// <param name="encryptKey1">密钥一</param>
        /// <param name="encryptKey2">密钥二</param>
        /// <param name="encryptKey3">密钥三</param>
        /// <returns>加密后字符</returns>
        public static string Encrypt(string encryptText, string encryptKey1, string encryptKey2, string encryptKey3)
        {
            string m_strEncrypt;
            try
            {
                m_strEncrypt = Encrypt(encryptText, encryptKey3);
                m_strEncrypt = Encrypt(m_strEncrypt, encryptKey2);
                m_strEncrypt = Encrypt(m_strEncrypt, encryptKey1);
            }
            catch (Exception ex) { throw ex; }
            return m_strEncrypt;
        }

        /// <summary>
        /// 3DES 解密(基于DES，对一块数据用三个不同的密钥进行三次加密，强度更高)
        /// </summary>
        /// <param name="decryptText">待解密密文</param>
        /// <param name="decryptKey1">密钥一</param>
        /// <param name="decryptKey2">密钥二</param>
        /// <param name="decryptKey3">密钥三</param>
        /// <returns>解密后字符</returns>
        public static string Decrypt(string decryptText, string decryptKey1, string decryptKey2, string decryptKey3)
        {
            string m_strDecrypt = "";
            try
            {
                m_strDecrypt = Decrypt(decryptText, decryptKey1);
                m_strDecrypt = Decrypt(m_strDecrypt, decryptKey2);
                m_strDecrypt = Decrypt(m_strDecrypt, decryptKey3);
            }
            catch (Exception ex) { throw ex; }
            return m_strDecrypt;
        }

        /// <summary>
        /// DES 加密(数据加密标准，速度较快，适用于加密大量数据的场合)
        /// </summary>
        /// <param name="encryptText">待加密的密文</param>
        /// <param name="encryptKey">加密的密钥</param>
        /// <returns>加密的字符</returns>
        public static string Encrypt(string encryptText, string encryptKey)
        {
            if (string.IsNullOrEmpty(encryptText)) { throw (new Exception("密文不得为空")); }

            if (string.IsNullOrEmpty(encryptKey)) { throw (new Exception("密钥不得为空")); }

            if (encryptKey.Length != 8) { throw (new Exception("密钥必须为8位")); }

            byte[] m_btIV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            string m_strEncrypt = "";
            DESCryptoServiceProvider m_DESProvider = new DESCryptoServiceProvider();
            try
            {
                byte[] m_btEncryptString = Encoding.Default.GetBytes(encryptText);
                MemoryStream m_stream = new MemoryStream();
                CryptoStream m_cstream = new CryptoStream(m_stream, m_DESProvider.CreateEncryptor(Encoding.Default.GetBytes(encryptKey), m_btIV), CryptoStreamMode.Write);
                m_cstream.Write(m_btEncryptString, 0, m_btEncryptString.Length);
                m_cstream.FlushFinalBlock();
                m_strEncrypt = Convert.ToBase64String(m_stream.ToArray());
                m_stream.Close(); m_stream.Dispose();
                m_cstream.Close(); m_cstream.Dispose();
            }
            catch (IOException ex) { throw ex; }
            catch (CryptographicException ex) { throw ex; }
            catch (ArgumentException ex) { throw ex; }
            catch (Exception ex) { throw ex; }
            finally { m_DESProvider.Clear(); }
            return m_strEncrypt;
        }

        /// <summary>
        /// DES 解密(数据加密标准，速度较快，适用于加密大量数据的场合)
        /// </summary>
        /// <param name="decryptText">待解密的密文</param>
        /// <param name="decryptKey">解密的密钥</param>
        /// <returns>解密的字符</returns>
        public static string Decrypt(string decryptText, string decryptKey)
        {
            if (string.IsNullOrEmpty(decryptText)) { throw (new Exception("密文不得为空")); }

            if (string.IsNullOrEmpty(decryptKey)) { throw (new Exception("密钥不得为空")); }

            if (decryptKey.Length != 8) { throw (new Exception("密钥必须为8位")); }

            byte[] m_btIV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            string m_strDecrypt = "";
            DESCryptoServiceProvider m_DESProvider = new DESCryptoServiceProvider();
            try
            {
                byte[] m_btDecryptString = Convert.FromBase64String(decryptText);
                MemoryStream m_stream = new MemoryStream();
                CryptoStream m_cstream = new CryptoStream(m_stream, m_DESProvider.CreateDecryptor(Encoding.Default.GetBytes(decryptKey), m_btIV), CryptoStreamMode.Write);
                m_cstream.Write(m_btDecryptString, 0, m_btDecryptString.Length);
                m_cstream.FlushFinalBlock();
                m_strDecrypt = Encoding.Default.GetString(m_stream.ToArray());
                m_stream.Close(); m_stream.Dispose();
                m_cstream.Close(); m_cstream.Dispose();
            }
            catch (IOException ex) { throw ex; }
            catch (CryptographicException ex) { throw ex; }
            catch (ArgumentException ex) { throw ex; }
            catch (Exception ex) { throw ex; }
            finally { m_DESProvider.Clear(); }
            return m_strDecrypt;
        }
        // 案例
        //string key_1 = "aaaaaaaa";
        //string key_2 = "bbbbbbbb";
        //string key_3 = "cccccccc";
        //string content = "张三";

        //string encryptResult = DESEncrypt.Encrypt(content, key_1, key_2, key_3);
        //Console.WriteLine(encryptResult); //结果显示: zQ71DHlFz6KqqKsg1J9jBYc+VRalcY48wXAGVGwNnhY=
 
        //string decryptResult = DESEncrypt.Decrypt(encryptResult, key_1, key_2, key_3);
        //Console.WriteLine(decryptResult); //结果显示: 张三
    }
}
